The present invention generally relates to a process for modifying polymeric amine salts. Further, the present invention is directed toward a modification process for neutralizing and hydroxylating a polymeric amine salt without generating a residual salt.
Polymeric amine salts containing reactive halide ions can present various problems in their utilization. For example, where a polymeric amine salt is employed in a coating for a metal substrate the halide ion can corrode the metal. This is due to the halide ion forming a hydrogen halide which has deleterious effects on the polymer as well as its environment.
Methods to neutralize polymeric amine salts have been attempted; unfortunately, they produce a by-product of the halide ion which is difficult to remove from the polymeric amine. For example, the neutralization of a polymeric amine salt produced by the acid hydrolysis of an amide containing polymer, is generally accomplished by reacting the hydrolyzed polymer with an inorganic base such as sodium hydroxide. Neutralization with the inorganic bases yields the free amine, but also yields the salt of the inorganic base. This by-product is difficult to remove and can act as a contaminant in the neutralized polymer.
Amide containing polymers can also be hydrolyzed under basic conditions. Unfortunately, this method yields a carboxylic acid salt. This by-product is also difficult to remove and can act as a contaminant in the polymer.
It, therefore, is desirable to neutralize polymeric amine salt without generating the difficult to remove salt contaminants. Additionally, it would be advantageous to be able to hydroxylate the neutralized polymer at the free amine site in a single operation.